Comparing topological charge definitions using topology fixing actions F. Bruckmann, F. Gruber, K. Jansen, M. Marinkovic, C. Urbach and M. Wagner Eur. Phys. J. A, 43 3 (2010) 303-311 Published online: 17 February 2010 DOI: 10.1140/epja/i2010-10915-1